SU8 submicron structures with an aspect ratio of more than 50 are made by soft X-ray lithography using modified spectra of the synchrotron radiation at the ANKA LITHO-1 beamline, which includes a chromium mirror. The X-ray spectrum is additional shaped by a beam stop and a filter to a narrow band in order to reduce the influence of diffraction and photoelectrons. The exposure determination is based on the measured threshold doses for used SU-8 resist layers as well as on the calculated diffractive distribution of an absorbed power. Post-exposure bake of the resist is performed at low temperature and low pressure to avoid changes of the structural size because of shrinkage due to temperature changes and to eliminate a ''skin'' layer at the top of the resist. SU8 structures with lateral dimensions of 1 lm and heights from 50 to 80 lm have been fabricated defect free with the optimized process.

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Deep X-ray lithography processing of SU-8 negative resist layers with thicknesses of up to 1 mm and physical-chemical properties of SU-8 polymer structures were investigated to find the optimum conditions for the fabrication of X-ray refractive lenses. The exposure was carried out at the ANKA storage ring in Karlsuhe, Germany. Experimental tests of the lenses were performed at the ESRF in Grenoble, France. First lenses showed a gain in the range of 20, a full width at half maximum of the focal spot intensity of approximately 2 lm to 3 lm and unique radiation stability of the optical characteristics. IntroductionThe idea of refractive X-ray lenses proposed in [1] was for the first time realized in form of consecutive holes in an aluminum block [2]. Unlike in case of visible light such an X-ray lens has to be composed of several elements with a concave shape. Their radius of curvature is in the range of several hundreds down to tens of micrometers. The lens material is absorbing. Since the first publication search and development of suitable materials and technologies for the formation of this simplest and cheapest type of X-ray optics is going on [3][4][5][6][7][8][9].Materials consisting of light atoms allow to reduce X-ray absorption and to increase the gain in the focal spot of an X-ray lens compared to heavier materials. Minimizing the bridge distance between adjacent concave shapes of an element of an X-ray lens leads to the same result. Besides, the exact patterning of the lens element form with the possibility of a coaxial arrangement of the elements is necessary in order to obtain the minimal size of a focal spot. A high roughness of the surface of the lens elements and a crystallinity of the lens material needs also to be avoided because it reduces the gain in the focal spot. In addition, expensive and materials unstable under X-ray exposure under normal conditions can not be used for this application. Depending on these evident limitations, planar lithographic technologies, especially deep X-ray lithography and LIGA technique would be a suitable process to pattern these elements. Structure characteristics as aspect ratios up to 100, sub-micrometer tolerance, smooth side-walls, vertical and tilted structures, sub-micrometer precision and exact positioning of the structures on a substrate are achieved by deep X-ray lithography in thick resist layers [10]. In principle, polymer X-ray resist materials composed from C, O and H atoms mainly are from the point of absorption competitive against the known lens materials as Li, Be, diamond, Al and Si. However, positive X-ray resists like PMMA which is conventional for X-ray lithography are destroyed under X-ray exposure in case of an absorbed radiation of already 1 kJ/cm 3 . This is insufficient even for a 1 h monochromatic X-ray experiment.A while ago the multi-component highly sensitive negative photo-resist SU-8 [11] was firstly proposed for deep X-ray lithography [12]. In our previous works [13,14] it has been shown that microstructures with aspect ratios of m...

Focusing planar refractive mosaic lenses based on triangular prism microstructures have been used as an alternative approach for wide-bandpass monochromatization of high-energy X-rays. The strong energy dependence of the refractive index of the lens material leads to an analogous energy dependence of the focal length of the lens. The refractive mosaic lens, in comparison with the refractive lens of continuous parabolic profile, is characterized by a higher aperture because of reduced passive material. In combination with a well defined pinhole aperture in the focal plane, the transmittance of photons of an appropriate energy can be relatively high and photons of deviating energy can be efficiently suppressed. The photon energy can be tuned by translating the pinhole along the optical axis, and the bandwidth changed by selecting appropriate pinhole aperture and beam stop. This method of monochromatization was realised at the ANKA FLUO beamline using a mosaic lens together with a 20 µm pinhole and beam stop. An energy resolution of 2.0% at 16 keV has been achieved.